Valve.



' No. 736,731. PATENTED APR. 4, 1905.

P. H. GRABTREE & A. G. MOGREGOR.

VALVE. APPLICATION FILED JUNE 21, 1904.

Nrrnn STATES,

Patented April 4, 1905..

PATENT @iuuoa.

FREDERICK HERBERT CRABTREE AND ALEXANDER GRAl lT MC-GREGORQ OF ANACONDA,MONTANA.

VALVE.

SPECIFICATION forming part of Letters Patent No. 786,731, dated April 4,1905, Application iiled June 21, 1904- *Serial No. 213,551.

T valve for automatically controlling the flow of steam from a boiler tothe main steam-pipe, although it may be used in various otherconnections where a fluid of any character is delivered under pressurefrom one vessel to another. I

A further object of the invention is to provide an improved automaticvalve mechanism of such nature that in the event of very low pressure inthe boiler, as in case where the fires of a boiler are drawn for thepurpose of cleaning or repairing the same or in case a tube shouldburst, the valve will automatically close and cut off communicationbetween the boiler and the main steam-pipe, this being of special valuewhere a battery of boilers is con nected to a single main.

A still further object'of the invention is to provide an improvedautomatic valve that will close when the difference in pressure in theboiler and in the main reaches a predetermined pointas, for instance, inthe event of the bursting of the main steam-pipe and consequent rapidexhaustion of steam from the boiler the valve will automatically closeand preventfurther escape of steam and the consequent damage resultingfrom such accidents.

A still further object of the invention is to provide an automatic valve.that will move from its seat understeam-pressure without danger ofchattering and under a predetermined normal pressure will maintain aninitial position and permit the free and unobstructed flow of the steamthrough the main steam-pipe.

A still further object of the invention is to provide an automatic valveof this character in which provision is made for accurately adjustingthe valve for closing movement at any predetermined point, and, further,to provide a valve which may be operated in the ordinary manner formanual closing when it becomes necessary to positively cut off the mainsteam-pipe. I

With these and other objects in view, as will more fully hereinafterappear, the invention consists in the novel construction and arrangementof parts hereinafter fully described, illustrated in the accompanyingdrawings, and particularly pointed out in. the appended claims, it beingunderstood that various changes in the form, proportions, size, andminor details of the structure may be made Without departing from thespirit or sacrificing any of the advantages of the invention.

In the drawings, Figure 1 is a longitudinal sectional elevation of anautomatic valve constructed in accordance with the invention. Fig. 2 isan end elevation of the same. Fig. 3 is a sectional plan view throughthe upper portion of the valve-casing. Fig. 4,- is a detail sectionalview of the valve-stem and one of its weights.

Similar numerals of reference are employed to indicatecorresponding'parts throughout the several figures of the drawings.

The valve-casing 1 is of the character ordinarily employed in largevalves and is provided With the usual bolting-flanges 2. The casing isprovided with a double valve-seat 3,

screwed or otherwise secured within the cas ing and provided with acentral guide for a valve-stem a, carrying a lower disk valve 5, adaptedto close against the lower seat. To this stem is further secured a diskvalve 6, that is adapted to close against .the upper valve-seat. Undernormal conditions the two valves will remain at points equidistant fromtheir respective seats and the steam may flow freely through the valve-casing to the main.

To the top of the valve-casing is secured a bonnet 7, and above thisis acap 8, carrying a yoke 9, the upper portion of which threaded for thereception of a threaded guide-stem 10, having ahand-wheel 11 of anyordinary construction. The cap is provided with a smiling-box 12 for thepassage of the stem 10, and the lower end of said stem has a reducedportion .13, that fits within a recess 14%, formed in the upper portionof a valvestem 15. The stem 15 has at its lower end a flange or collar17, that is held down within a socket in the central portion. of thevalve 6 by means of a threaded sleeve 18, thus forming a swiveledconnection which will permit of rotatable movement of the stemindependently of the valve, if necessary. Under normal conditions theconnection between the stems 13 and 15 is such as to permit freelongitudinal play of the stem 15 as the valve-- disks 5 and 6 movevertically under variations in the steam-pressure; but when necessarythe hand-wheel 11 may be turned and the stem 10 forced down until theshoulder 19 of the stem engages a collar 20 at the upper end of the stem15 and forces said stem and the Valve 6 downward until the latter isfirmly pressed against the upper valve-seat and positively cuts offcommunication between the boiler and the main steam-pipe.

The lower portion of the bonnet 7 has an inwardly-extending annularflange 22, on which rests a cylindrical weight 23, having a centralopening for the passage of the valvestem 15, and on said valve-stem isan enlarged collar or flange 24;, which is in engagement with andpresses lightly against thebottom. of the weight when the two valves arein the normal position shown in Fig. 1.

On one side of the bonnet is an offset por-- tion having bearings forthe reception of a horizontally-disposed rock-shaft 27, to which issecured a rocker-arm 28, having a bifurcated portion. embracing theupper portion of the stem 15 at a point immediately below the collar 20.One end of the shaft projects through the open end of the offset portionand is held in place by a gland-nut 29, and at the outer end of saidshaft is secured a rocker arm 30, resting on a supporting-bracket 35 andcarrying an adjustable weight 31, the weight being placed at such adistance from the fulcrum-point that it will just about counterbalancethe weight of the two valves 5 and 6 and the stem 15. The result of thisis that when there is comparatively little flow from the boiler thevalves will open to the position shown in Fig. 1 without danger ofchattering. The rocker-arm 30 in this position rests on a stop 32,carried by the valve-casing.

.lln. the operation of the device steam under ordinary pressure isallowed to pass freely from the boiler to the main; but should. the tireof the boiler be drawn or the pressure reduced to any material extentthe back pressure of the main, especially when the latter is connectedto a battery of boilers, will force the two valves downward until thevalve 6 closes against its seat, and when once closed the pressure inthe main will hold it there until the pressure of the boiler is againrestored.

If the pressure in the boiler greatly exceeds that in the mainas, forinstance, when the main is broken and there is a quick rush of steamfrom the boiler--- the outliowing steam will raise the valves againstthe downward pressure of the weight 523 and will force the valve 5 toits seat and maintain the said valve in closed position until thepressure in the main has been restored to the normal, so that nomanipulation by the att-emlnnt is required in cutting in orcutting out aboiler and mini mixing the result of neglect, ignorance, orcurelessness.

The valve is so constructed as to avoid the use oi all closely-fittingpistons or like members which are likely to corrode or otherwisedeteriorate to such an extent as to stick in previously adjustedpositions and prevent movement to closed positions when occasionrequires.

Having thus described the invention, what is claimed is 1. incombination, a valve-casing, a valve, and a pair of normally inactiveweights lending to maintain the valve in a predelm'mined position, oneor other of the weights being imposed on the valve when the latter movesfrom such position.

2. A valve, and apair of weights connected to the stem 01 the valve, andacting, respectively, in opposite directions on the stem, one or otherof the weights being imposed on the stem when the valve moves in eitherdirection.

3. The combination with a valve-casing, ol" a pai r of valve-seats, apair of valve-disks1nov able respectively in opposite directions toclosed positions, a stem connecting the valves, a rocker-shaft, arocker-arm carried by the shaft and connected to the stem, a secondrocker-arm also connected to the shaft and provided with an adjustablecounterweight, and a stop or rest for the second rocker-arm when thevalve is in mid'position.

1. The combination with a valve-casing,having a pair of valve-seats,ol apair of disk val vvs, a stem connected to the same, an enlarged collaror flange at the outer end of the stem, :1 rock-shaft, a bifurcatedrocker-arm engaging on the collar, said arm being secured to the shaft,a second rocker-arm extending outside the valve-casing, and anadjustable counterweight carried by the second rocker-arm.

5. The combination with a valve-casinghaving a pair of valve-seats, of apair ol'd isk valves movable respectively in opposite directions toclosed position, a stem connected to the two valves and provided with anenlarged llange or collar, a rock-shaft having one end extend ingthrough the upper portion of the valvecasing, a rocker-arm connected tothe inner end of said shaft and having a bifurcated portion inengagement with the collar, a second rocker-arm connected to the outerportion of the shaft, and a counterweight carried by the secondrocker-arm.

6. Thecombination with avalve-casinghaving apair of val ve-seats, of apair of disk valves movable respectively in opposite directions toclosed position, a bonnet secured to the casing and having an offsetportion, a rock-shaft ex" .tending into said offset portion and providedwith an enlarged collar or flange, a clamp-nut surrounding a portion ofthe shaft and engaging the end of the collar to retain the shaft inposition, a pair of rocker-arms carried by the shaft one of saidrocker-arms engaging the stem, and a counterweight adjustably secured tothe second rocker-arm.

7. In valve mechanisms, a casing, a valve, and a weight having aslidable connection with the valve to permit the free movement of thevalve in one direction and limited movement in the opposite direction,said weight being imposed on the valve when the latter is moved beyondthe normal limit in said opposite direction.

8. In valve mechanisms, a casing having a valve-seat, a valve free tomove with respectto the valve-seat, and a weight for limiting themovement of the valve, said weight being imposed on the valve only whenthe latter exceeds its normal limit of movement.

9. The combination with a valve-casing having a pair of valve-seats, ofa pair of valves movable respectively in opposite directions to closedposition, a valve-stem, and a weight having an opening for the passageof the stem therethrough to permit freedom of movement ofthe valves to alimited extent, the weight being imposed on the stem when such limit ofmovement is exceeded.

10. The combination with a valve-casing having a pair of valve-seats, ofa pair of valves movable, respectively, in opposite directions to closedpositions, a stem connecting the valves, and means for counterbalancingthe weight of the valve and stem, a bonnet connected to thevalve-casing, a loose weight arrangedwithin the bonnet and having anopening for the free play of the valve-stem, and an enlarged collar orflange carried by the valvestem for engaging and raising the Weight whenthe valve exceeds its normal limit of" movement.

11. The combination with a valve-casing having a pair of valve-seats, ofa pair of valves movable, respectively, in opposite directions to closedposition, a valve-stem connected to both valves and having alongitudinal opening. and a manually-operable threaded stem havingareduced portion fitting in said opening. i

12. The combination with a valve-casing having a pair of valve-seats, ofa pair of valves, a recessed stem carrying said valves, means forcounterbalancing the weight of the valves, a stem, a second weighthaving an opening for the passage of the stem, a collar secured to thestem and serving to engage and raise the weight when the valve-stemexceeds its normal limit of movement in one direction, and amanually-operable threaded stem having a reduced end fitted within thehollow valvestem. I

In testimony that we claim the foregoing as our own we have heretoaflixed our signatures in the presence of two witnesses.

HIRAM W. RoDeERs, OWEN C. GRAW.

